[tests] Using unique permutations in tests

Author: LucianoPAlmeida

Tests/SwiftAlgorithmsTests/CompactedTests.swift

@@ -14,17 +14,10 @@ import Algorithms
 
 final class CompactedTests: XCTestCase {
 
-  var tests: [[Int?]] = [
-    [],
-    [0],
-    [nil],
-    [0, nil],
-    [nil, 0],
-    [0, nil, 1, nil, 2, nil],
-    [0, 1, 2, nil, nil, nil],
-    [nil, nil, nil, 0, 1, 2],
-    [nil, nil, nil, nil, nil, nil]
-  ]
+  let tests: [[Int?]] =
+    [nil, nil, nil, 0, 1, 2]
+        .uniquePermutations(ofCount: 0...)
+        .map(Array.init)
 
   func testCompactedSequence() {
     for array in self.tests {